Knox County schools graduated in May 2015. The clerk was lucky her armed friend was there. If she had been shot she could have likely bled out that time of night before the next customer came in. There's a Wendy's and a car parts store at the intersection the store is at and nothing else. If someone pulls a firearm or a knife on a clerk there is reason to believe they will be shot.
The real tragedy that happened was within a few hundred feet from this store was this school year when two school buses collided and several kids and a school employee died. Now that was true innocents being killed.